We propose to continue our basic research toward understanding member assembly and member protein-lipid interactions. Because of its simplicity of structure, the formation of the membrane-containing bacteriophage PM2 offers a unique system to focus on the molecular basis for membrane biogenesis and interaction of membrane proteins with membrane lipids. In particular, we ask the question, "What controls the size, shape and composition of a biological membrane?" The power of bacteriophage genetics involving conditional-lethal membrane mutants is utilized in order to dissect the control of membrane biogenesis and membrane protein-lipid interactions. Results to date characterizing mutant ts1 of PM2 indicate that the 6,600 dalton structural protein of the virus may contain the information required for making a membrane of the desired size, shape and composition. The construction of a Pseudomonas BAL-31 host bearing a suppressor will permit the isolation of amber mutants of PM2. Biochemical studies of the assembly of the PM2 membrane will proceed by radio-labeling viral proteins as they are synthesized and determining their temporal associations with the host membrane. Membrane morphogenesis will be studied by electron microscopy of membranes of infected cells labeled with ferritin-conjugated antibodies to the viral structural proteins. The physical-chemical basis for membrane assembly will be determined by examining the phospholipid binding specificity of an integral membrane protein of PM2.